Many of the management practices to which livestock are subjected during the marketing period, particularly in the antemortem environment, can be potent physiological and psychological stressors (see Kilgour, 1988; Warris 1986; Fraser, 1979; Stermer et al., 1982; Kent et al., 1986; Mikulik et al., 1987; Kenney et al., 1987; Loccatelli et al., 1987; Cole et al., 1988; and Eldridge, 1988). Factors such as the withholding of feed (Ozutsumi, 1984; Schaefer et al., 1988; Jones et al., 1988; and Jones et al., 1990), mixing of unfamiliar animals (Eldridge, 1988), fighting (Unanua et al., 1985), as well as transport and weather (Jones et al., 1989) are commonly reported insults which can lead to abnormal physiology in these animals, carcass loss and degraded meat quality. In cattle, it has been demonstrated that handling and transport per se can be more potent stressors, based on blood cortisol levels, than 48 hours of water withdrawal or surgical castration and dehorning (Johnston et al., 1976). In addition to the above, there is a growing concern that animal welfare in the pre-slaughter environment may be degraded.
A substantial scientific effort has been made to identify and document the kinds and nature of responses to antemortem stress. Such work has included an examination of the role of sodium, potassium and fluid shifts (Ruppanner et al., 1978; Jagos et al., 1985; Post 1965; and Armentano et al., 1987) and acid/base and electrolyte values associated with poor meat quality (Schaefer et al., 1988; and Jones et al., 1988). However, the assessment of management practices that would reduce or eliminate these stressors has been less well understood. With the exception of research on the use of high energy feeds (Morisse et al., 1985; Hutcheson et al., 1986; and Wajda et al., 1987) few studies have been undertaken to specifically improve carcass yield and meat quality by manipulating pre-slaughter nutrition and electrolyte management in the antemortem environment.
In a 1988 study (Schaefer et al., 1990) involving two of the inventors, animals which had been subjected to transport stress were treated with solutions containing glucose or a mixture of electrolytes and food grade pure sources of amino acids. The results showed some apparent improvement in meat quality and carcass yield with the glucose and electrolyte treatments. No benefit was reported from the inclusion of food grade amino acids. Importantly, this study was restricted to a restorative approach to improving meat quality and carcass yield, that is the compositions were provided to animals only after the animals had experienced stresses approximating the antemortem environment.
The literature discloses electrolyte compositions for use in the treatment of diseased states in animals, for instance diarrhea or dehydration (see for example U.S. Pat. No. 5,008,248 to Bywater et al.; U.S. Pat. Nos. 4,981,687 and 5,089,477 to Fregly et al.; U.S. Pat. No. 5,028,437 to Jerrett; U.S. Pat. No. 4,839,347 to Franz and published European Patent Application No. 84300179 to TechAmerica Group Inc.). Electrolyte compositions are also taught to enhance athletic performance in humans or race horses (see for example U.S. Pat. No. 4,853,237 to Prinkkila et al.; and U.S. Pat. No. 4,871,550 to Millman). Since the nature of antemortem stress is uniquely different from other types of stress such as clinically identified disease or the desire to enhance athletic performance, the prior art compositions formulated for such different utilities are not applicable for the treatment of antemortem stress. Such prior art compositions often include ingredients in ineffective or harmful concentrations. For instance, many of the compositions include electrolytes in high concentrations which would be hypertonic and damaging to otherwise healthy animals. Also, such compositions often include other ineffective and potentially harmful ingredients for otherwise healthy animals, including caffeine, citric acid, pyruvate, and glycerol.
There is a need for a composition which has a preventative effect in reducing the antemortem stress causes of degraded meat quality and decreased carcass yield.